• 전기학회논문지
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• 제60권2호
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• pp.362-369
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• 2011

In this paper, optimal deep reactive ion etching (DRIE) process conditions for fused quartz were experimentally determined by Taguchi method, and fused quartz-based micro cantilevers were fabricated. In addition, comparative study on Q-factors of fused quartz and silicon micro cantilevers was performed. Using a silicon layer as an etch mask for fused quartz DRIE process, different 9 flow rate conditions of $C_4F_8$, $O_2$ and He gases were tested and the optimum combination of these factors was estimated. Micro cantilevers based on fused quartz were fabricated from this optimal DRIE condition. Through conventional silicon DRIE process, single-crystalline silicon micro cantilevers whose dimensions were similar to those of quartz cantilevers were also fabricated. Mechanical Q-factors were calculated to compare intrinsic damping properties of those two materials. Resonant frequencies and Q-factors were measured for the cantilevers having fixed widths and thicknesses and different lengths. The Q-factors were in a range of 64,000 - 108,000 for fused quartz cantilevers and 31,000 - 35,000 for silicon cantilevers. The experimental results supported that fused quartz had a good intrinsic damping property compared to that of single crystalline silicon.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.129-130
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• 2008

In this paper, optimal DRIE process conditions for fused quartz are experimentally determined by Taguchi method to develop high-performance inertial sensors based on the fused quartz material, which is known to have high Q-factors. Using Si layer as an etch mask, which was formed by previously developed bonding process of the fused quartz and Si wafer, fused quartz DRIE process was performed. Different 9 flow rate conditions of $C_4F_8$, $O_2$, He gas have been tested and the optimum combination of these factors was estimated. By this work, the ability to fabricate high aspect ratio fused quartz structure was confirmed.

• Applied Biological Chemistry
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• 제14권3호
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• pp.183-189
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• 1971

규산재료(珪酸材料)인 강사(江砂) 및 석영(石英)과 농용(農用) 소석회(消石灰)의 혼합(混合) 용융물(溶融物)에 대(對)한 규산질(珪酸質) 비료(肥料)로써의 효과(效果)를 구명(究明)코져 유효규산함량(有效珪酸含量)이 낮은 답토괴(畓土壞)에서 수도(水稻)에 대(對)해서 천연(天然) 규회석(珪灰石)을 대조(對照)로 시비처리(施肥處理)하여 시험(試驗)한 결과(結果) 1. 모래용융물(溶融物)이 석영용융물(石英溶融物)에 비(比)하여 N/2 염산가용규산함량(鹽酸可溶珪酸含量)이 높고 2% 구연산 가용규산함량(可溶珪酸含量)은 석영용융물(石英溶融物)이 모래용융물(溶融物)보다 높았다. 2. 벼의 규산흡수량(珪酸吸收量)은 석영용융물(石英溶融物)에서 가장 크고 모래용융물(溶融物)과 규회석(珪灰石)은 거의 같았으며 이용율(利用率)은 천연(天然) 규회석(珪灰石)이 가장 높고 석영용융물구(石英溶融物區)가 모래용융물구(溶融物區)보다 높았다. 3. 정조수량(正租收量)은 규산물질(珪酸物質)의 시용(施用)으로 수량구성요소중(收量構成要素中) 수당입수(穗當粒數), 등숙률(登熟率) 및 천입중(千粒重)의 증가(增加)로 증수(增收)되었으며 공시재료중(供試材料中) 석영용융구(石英溶融區)에서 가장 크게 증수(增收)하였으며 대조구(對照區)${\fallingdotseq}$모래용융물(溶融物) 100kg/10a<천연규회석(天然珪灰石)${\fallingdotseq}$모래용융물(溶融物) 300kg/10a${\fallingdotseq}$석영용융물(石英溶融物) 100kg/10a<모래용융물(溶融物) 500kg/10a${\fallingdotseq}$석영용융물(石英溶融物) 300kg/10a<석영용융물(石英溶融物) 500kg/10a의 순서(順序)이었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1505_1506
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• 2009

In this paper, micro cantilevers which are made of two different materials - fused quartz and single crystalline silicon - and have similar dimensions were fabricated and their mechanical Q-factors were evaluated to compare intrinsic damping properties of those two materials. Resonant frequencies and Q-factors were measured for the cantilevers having fixed widths and thicknesses, and different lengths. The measured Q-values are in a range of 64,000 - 108,000 for fused quartz cantilevers, and 31,000 - 35,000 for silicon cantilevers, respectively. Experimental results support high Q-factors of fused quartz compared to single crystalline silicon due to its good intrinsic damping properties.

• 소성∙가공
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• 제11권7호
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• pp.601-607
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• 2002

Optically transparent materials such as fused silica, quartz and crystal have become important in the filed of optics and optoelectronics. Laser ablation continues to grow as an important technique for micromachining and surface modification of various materials, because many problems caused by direct contact between tools and workpiece can be avoided. Especially, laser ablation with excimer lasers enables fine micromachining of transparent materials such as fused silica, quartz and crystal, etc. In this study, laser-induced wet etching of fused silica in organic solution was conducted. KrF excimer laser was used as a light source and acetone solution of pyrene was used as etchant. Changing the number of laser pulses, micro holes of various depths are fabricated.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.705-710
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• 2001

So for the quartz-glassy crucible wastes which was used for pulling up silicon-single-crystal ingot have simply reused for refractory raw-materials, or exhausted. This study is concerned on the advanced recycling-technology that is obtained by the proper micro-particle preparation process in order to fabricate fine amorphous silica filler for EMC (Epoxy Molding Compound). Therefore, this paper will deal with the physical, chemical and thermal pre-treatment process for efficient impurity removal and with the proper micro-particle process for producing the amorphous silicafiller. In view of the results, if the chemical, physical and thermal pre-treatment process for efficient elimination of impurity was passed, the purity of wasted fused glassy crucible is almost equal to the its of first anhydrous quartz glass. Thus, it was understood that this wasted fused glassy crucible was sufficient value of recycling, though it was damaged. When the ingot was fabricated, Phase transformation of crystallization by heat treatment (heat hysteresis phenomenon) was not changed. So, it was understood that as fused silica in the amorphous state, as It is, recycling possibility was very high

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1103-1107
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• 2005

Single-crystal silicon thin films on glass (SOG) and on fused-quartz (SOQ) were prepared using wafer bonding and hydrogen-induced layer transfer. Thinfilm transistors (TFTs) were subsequently fabricated. The high-temperature processed SOQ TFTs show better device performance than the low-temperature processed SOG TFTs. Tensile and compressive strain was measured respectively on SOQ and SOG. Consistent with the tensile strain, enhanced electron effective mobility was measured on the SOQ TFTs.

• 한국재료학회지
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• 제13권9호
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• pp.606-612
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• 2003

Surface and mechanical properties of thin films with submicron thickness was characterized by nanoindentation with Berkovich and Vickers tips, and scanning probe microscopy. Nanoindention was made in a depth range of 15 to 200 nm from the surface by applying tiny force in a range from 150 to $9,000 \mu$N. Stiffness, contact area, hardness, and elastic modulus were determined from the force-displacement curve obtained. Reliability was first tested by using fused quartz, a standard sample. Elastic modulus and hardness values of fused quartz measured were the same as those reported in the literature within two percent of error. Mechanical properties of ITO thin film were characterized in a depth range of 15∼200nm. As indentation depth increased, elastic modulus and hardness decreased by substrate effect. Ion beam deposited DLC thin films were indented in a depth range of 40∼50 nm. The results showed that the DLC thin film using benzene and bias voltage 0∼-50 V has elastic modulus and hardness value of 132 and 18 GPa respectively. Pure DLC thin films showed roughnesses lower than 0.25 nm, but silicon-added DLC thin films showed much higher roughness values, and the wavy surface morphology.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.835-841
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• 2013

Modern solid-state gyroscopes (HRG) with hemispherical resonators from high-purity quartz glass and special surface superfinishing and ultrathin gold coating become the best instruments for precise-grade inertial reference units (IRU) targeting long-term space missions. Designing of these sensors could be a notable contribution into development of Korea as a space nation. In participial, 40mm diameter thin-shell resonator from high-purity fused quartz, fabricated as a single-piece with its supporting stem has been designed, machined, etched, tuned, tested, and delivered by STM Co. (ATS of Ukraine) several years ago; an extremely-high Q-factor (upto 10~20 millions) has been shown. Understanding of the best way how to match such a unique sensor with inner glass assembly of the gyro means how to use the high potential in a maximal extent; and this has become the urgent task. Inner quartz glass assembly has a very thin indium (In) layer soldered the resonator and its silica base (case), but effects of internal resonances between operational modal pair of the shell-cup and its side (parasitic) modes can notable degrade the potential of the sensor as a whole, instead of so low level of resonator's intrinsic losses. Unfortunately, there are special combinations of dimensions of the parts (so-called, "resonant sizes"), when intensive losses of energy occurs. The authors proposed to use the length of stem's fixture as an additional design parameter to avoid such cases. So-called, a cyclic scheme of finite element method (FEM) and ANSYS software were employed to estimate different combinations of gyro assembly parameters. This variant has no mismatches of numerical origin due to FEM's discrete mesh. The optimum length and dangerous "resonant lengths" have been found. The special attention has been paid to analyses of 3D effects in a cup-stem transient zone, including determination of a difference between the positions of geometrical Pole of the resonant hemisphere and of its "dynamical Pole", i.e., its real zone of oscillation node. Boundary effects between the shell (cup) and 3D short "beams" (inner and outer stems) have been ranged. The results of the numerical experiments have been compared with the classic model of a quasi-hemispherical shell band with inextensional midsurface, and the solution using Rayleigh's functions of the $1^{st}$ and $2^{nd}$ kinds. To guarantee the truth of the recommended sizes to a designer of the real device, the analytical and FEM results have been compared with experimental data for a party of real resonators. The consistency of the results obtained by different means has been shown with errors less than 5%. The results notably differ from the data published earlier by different researchers.

• 한국음향학회지
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• 제20권1호
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• pp.62-67
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• 2001

직선집속 PVDF 초음파 트랜스듀서를 이용하여 누설탄성표면파 (Leaky Surface Acoustic Wave: LSAW)의 전파속도를 측정하고, 그 결과를 이론해석 결과와 비교하였다. 시료로는 등방성 재료인 구리, 알루미늄 및 용융석영, 이방성 재료인 Z-cut α/sup-/수정을 사용하였다. 측정방법으로는 초점면에 위치한 시료를 트랜스듀서 쪽으로 접근시켰을 때 LSAW가 트랜스듀서의 중심축을 통과한 후 시료표면에서 직접 반사되어오는 종파와 분리되어지는 현상을 이용하였다. 음속의 측정결과는 이론 해석결과와 오차 1％이내에서 잘 일치하였으며,α/sup-/수정의 (0,0,1)면에서는 LSAW 외에 의사누설탄성표면파 (Leaky Pseudo Surface Acoustic Wave : LPSAW)가 전형적인 6-fold 이방성을 가지고 전파됨을 알 수 있었다.